Field of the Invention
The present invention relates generally to computer-aided manufacturing and, more specifically, to optical measurement of object location in three dimensions.
Description of the Related Art
When analyzing interactions between a workpiece and a part of a robot configured to manipulate or process the workpiece, such as a robotic arm, it is oftentimes useful to determine the locations of the tips, edges, or other extremities of the object. Quantifying such locations based on precise measurements of the workpiece can aid the robotic arm in manipulating and otherwise processing the workpiece. For example, based on the location of the workpiece relative to the robot, the robot can relocate, translate, rotate, and otherwise orient the workpiece in such a way as to avoid interferences between the workpiece and known obstructions proximate the robot. In addition, precise knowledge of the location of a workpiece being manipulated or processed by the robot increases the safety of workers or other bystanders in the vicinity of the robot.
Conventional approaches for locating an object being manipulated by a robot, such as a workpiece being held and processed by the robot, often require multiple time-consuming measurements to be performed using expensive equipment. For example, in calibrating the location of a workpiece associated with a robot, a computer numerical control (CNC devices), or other technically-feasible computer-aided device, locations are measured via touch-based measurements. Such touch-based measurements require expensive, highly-engineered and instrumented machinery and generally require multiple distinct measurements to be performed for each point or feature to be located on the workpiece. For example, to determine the location of one point or feature on the workpiece, the workpiece may be physically touched multiple times to a first sensor to determine a location with respect to a first dimension, multiple times to a second sensor to determine a location with respect to a second dimension, and multiple times to a third sensor to determine a location with respect to a third dimension. Each such measurement procedure is time-consuming, and is typically performed multiple times on a single workpiece.
Other conventional approaches exist for measuring the dimensions or location of an object in multiple dimensions simultaneously. However, such approaches generally involve complex machinery, where the object is required to remain stationary for a particular time interval while the multiple measurements are being made. For example, a camera may be revolved around the workpiece or multiple stationary cameras may capture images of the workpiece from multiple viewpoints. Such approaches often involve complex technologies that require time-consuming and complex set-up, calibration, and troubleshooting, such as laser-based scanning.
As the foregoing illustrates, what is needed in the art are more effective techniques for measuring the location of a workpiece being manipulated or processed by a robot.